Divide ribs into 6-7" sections.
Press Sauté (set to Normal).
Cover bottom of the pot with vegetable oil and let heat for 90 seconds.
Add one section of rib. Let cook for 3 minutes on each side, remove section to a clean plate. Repeat for each section, adding vegetable oil as needed.
Remove inner pot and carefully dispose of used oil. Wash pot with dish detergent and hot water. Rinse & dry completely. Replace in Instant Pot.
Stack rib sections into clean inner pot.
In a bowl, whisk 1/2 cup barbecue sauce, salt and root beer then pour over the stack of ribs in the inner pot.
Close & lock the lid.
Turn steam release valve to Sealing.
Select Pressure Cook–High & set timer for 45 minutes.
Allow Natural Release for 10 minutes.
Press steam release valve to initiate Quick Release.
Press Cancel and Keep Warm.
Remove ribs, place on cutting board and let cool to warm.
Simmer 10-12 minutes, whisking frequently until thickened. Reduce to about 2 cups of sauce.
Add remaining BBQ sauce, mixing well.
Place ribs into a large pan then pour the sauce over them.